SURFACE TENSION DRIVEN WATER PUMPING by J. Fraser

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SURFACE TENSION DRIVEN WATER PUMPING byJ.
Fraser R.T. Dobson

• University of Stellenbosch

Energy Postgraduate Conference 2013
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Overview

• Introduction
• Background and Objectives
• Main Theory
• Problems
• Why it works
• Conclusion

• Falling water droplet

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Introduction

• Nature has adapted of millions of years
• Humans can learn much from nature
• Biomimicry nature inspired design

• Examples
• Elephant trunk
• Gecko feet
• Shark skin
• Lotus leaves
• Beehive structure
• Insect Nano robots
• And many more

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Introduction (cont.)

• Surface tension similar to elastic membrane on
  fluid surface
• Nature found myriad of exploitations
• Small insects stride on water
• Bacteria releases surfactant for driving force
• Some larva employs vector control for propulsion
• Recent applications
• Small object propulsion
• Nano-robots maneuverability
• Capillary action
• Micro pumping
• etc

• Plant life thrived on Earth for
• thousands of years
• Pump water seemingly effortlessly
• Giant Redwoods grow up to 100 m tall
• Useful mechanism for water pumping
• In a time of water shortages,
• climate change, power consumption
• and emmision concerns

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Background Objectives

• Plant Leaves
• Photosynthesis water carbon dioxide energy ?
  carbohydrates oxygen
• Ingenious water transport mechanism of plants
• Capillary-driven heat pipe technology mechanisms
• Construct mechanical/artificial pump
• First step in a larger project
• wherein hydrogen, food (carbohydrates) and fuel
  are artificially produced.
• For this project
• build mechanically-constructed experimental
  simulation working model of transport mechanism
• Theoretical thermal-hydraulic simulation model
  validation against experimental model.
• After validation use of such a water pump in an
  artificial photosynthesis program to be
  established.

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Main Theory Overview

• Water Transport
• in trees
• ? Transpiration pull
• (TACT)
• Transpiration
• Adhesion
• Cohesion
• Tension

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Problems
 
 
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Why it works
 
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Why it works

• Secret
• ? Strong adhesion forces
• Strong cohesion forces
• ? Evaporation
• ? Surface tension forces
• Must prevent nucleation sites
• Prevent embolisms
• Require a continuous channel of water
• Rerouting
• Dissolve bubbles

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In Conclusion

• Nature offers many lessons and techniques
• Surface tension useful
• mechanism
• Tree water pumping
• mechanism
• investigation
• Theory, build,
• experiment
• validate

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Acknowledgements

• Mr. Dobson
• Family

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END

• THANK YOU